From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED!not-for-mail From: Steve Fink Newsgroups: gmane.emacs.devel Subject: Re: [EXPERIMENT] Emacs with the SpiderMonkey garbage collector Date: Thu, 30 Nov 2017 17:03:51 -0800 Message-ID: <11bad7d0-fdc1-6462-1520-759ac54bc7c2@gmail.com> References: <9d7be625-85ae-54d5-3897-6f701c8ea124@cs.ucla.edu> NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit X-Trace: blaine.gmane.org 1512164252 27236 195.159.176.226 (1 Dec 2017 21:37:32 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Fri, 1 Dec 2017 21:37:32 +0000 (UTC) User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.3.0 To: emacs-devel@gnu.org Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Fri Dec 01 22:37:29 2017 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1eKszr-0006an-Ko for ged-emacs-devel@m.gmane.org; Fri, 01 Dec 2017 22:37:23 +0100 Original-Received: from localhost ([::1]:33134 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eKszy-0006js-VD for ged-emacs-devel@m.gmane.org; Fri, 01 Dec 2017 16:37:31 -0500 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:52483) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eKqHp-0004tY-Ct for emacs-devel@gnu.org; Fri, 01 Dec 2017 13:43:46 -0500 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1eKqHm-0002HP-1w for emacs-devel@gnu.org; Fri, 01 Dec 2017 13:43:45 -0500 Original-Received: from mail-pf0-x22c.google.com ([2607:f8b0:400e:c00::22c]:35071) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1eKqHl-0002HH-S2 for emacs-devel@gnu.org; Fri, 01 Dec 2017 13:43:41 -0500 Original-Received: by mail-pf0-x22c.google.com with SMTP id j124so5014825pfc.2 for ; Fri, 01 Dec 2017 10:43:41 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=references:to:from:subject:message-id:date:user-agent:mime-version :in-reply-to:content-transfer-encoding:content-language; bh=5tnIqYdwiGng+SpUiU9UwWFSVnUts6DYeFrMWswgAt8=; b=QgaGVzCJoc8BpfwRlSa09kMV9l+YAOtH2WPpq+vaJouQmjRDpBa4zRPeRtVEegEugt ytaCoGTcpnFtr0zkiKRMc1qbhRG8fA5ZNtfBMTOo/2UyqI7Sh3JoflGOjSUxGLrwb3h1 LK/dDYrwV8NTMffQD8XKkR6wlhocl3Br3EjnuglbI5nqWI2F9QDUlAEBBOvGl0qWK5/q 2rfA0tkyq3w6VdBmXB0oIA4YdcA4/D2JaLGgcI+u6DAEEAP9GGPElHj3PsoqftAdiO/P XT2z+Xl3z44dHm6ZTj51dsEjd8tj4cO7Q1y/9J5AlXKXFM8Ij802gx/KX86jns/h+GQ4 C2Xg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:references:to:from:subject:message-id:date :user-agent:mime-version:in-reply-to:content-transfer-encoding :content-language; bh=5tnIqYdwiGng+SpUiU9UwWFSVnUts6DYeFrMWswgAt8=; b=IL9kvonmc+YkCdOw2PMLWe+m6QwxdVf4pplmKhf2ehfWtKV1PJ6c8r9hIC3jdv8Iqf MvoMA02nkM14PxlFvw3+iRB3r258LwvZTfDuurOoZ9dXRCarBMLo0LRMXD37UtDnQbvK 1EIX9R2OZjS1uP6fZxZHmhxerSBitTqhWvnW8ZJ1J6WMQUIrVbPg9L3JMtg6frxdtPnG uRxw+eeAmCdAIdKVTMcU/a2bDrRrnpnIYuLXZXmN52olvxa3/nRPb7o6KcTJSG0ZLOqG hy1ipJDLIaBoeT7FDlfmbcN5izLSkDQsj/QGYdXPPLTG9XK+x2QpmuQcTx5M8REHQaiC 45ng== X-Gm-Message-State: AJaThX4T/Eyudx1hfq886MbaIlkQdDbqqmz2GD0aMojENFl0e8uAyAJb JDbqjB7cI8zwaeRJfXWysP8XRjge X-Google-Smtp-Source: AGs4zMYg19Pp/KdMMQneSDsoGHkLGbXaq6iDNe/yQrRm9vvydBGVG7qbrbCnEcOO5TSm/u5Jsszamw== X-Received: by 10.98.153.18 with SMTP id d18mr8477939pfe.145.1512090234641; Thu, 30 Nov 2017 17:03:54 -0800 (PST) Original-Received: from [10.0.0.108] (107-207-38-202.lightspeed.sntcca.sbcglobal.net. [107.207.38.202]) by smtp.googlemail.com with ESMTPSA id u125sm9653071pgc.94.2017.11.30.17.03.52 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 30 Nov 2017 17:03:53 -0800 (PST) In-Reply-To: Content-Language: en-US X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 2607:f8b0:400e:c00::22c X-Mailman-Approved-At: Fri, 01 Dec 2017 16:33:32 -0500 X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Original-Sender: "Emacs-devel" Xref: news.gmane.org gmane.emacs.devel:220595 Archived-At: > - during GC you need *double* the heap space. If you only GC a sub-part > of your heap (e.g. just one generation), then you only need double > that sub-part. So if you only use a copy-GC for the youngest generation > it's not a big deal, but if you use stop© over your whole heap, > we're talking about a 100% overhead on memory usage. Yes. The Spidermonkey GC uses moving collection for the nursery generation and nonmoving collection for the tenured heap, though it will also periodically do a compacting GC of the tenured heap that moves things. But the compacting GC breaks the heap into small chunks, so the overhead is at most one of those chunks. And it doesn't do semispace collection; it moves everything from the nursery to the tenured heap, so you don't need double the nursery size ever. (Not that the nursery is fixed size; it'll double itself if you're filling it up fast, up to a maximum size.)